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Trial registered on ANZCTR

Registration number
Ethics application status
Submitted, not yet approved
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Effectiveness and cost-effectiveness of telephone support with Short Message Service (SMS) in preventing obesity of children aged 2-3 years
Scientific title
Effectiveness and cost-effectiveness of maternal telephone support with Short Message Service (SMS) in preventing obesity of children aged 2-3 years: a randomised controlled trial
Secondary ID [1] 296070 0
Universal Trial Number (UTN)
Trial acronym
Linked CHAT
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Child overweight and obesity 309627 0
Condition category
Condition code
Diet and Nutrition 308441 308441 0 0
Public Health 308492 308492 0 0
Health promotion/education

Study type
Description of intervention(s) / exposure
This is a two-arm/parallel randomised controlled trial (RCT).

The proposed intervention is based upon the principles of the successful Healthy Beginnings Trial (HBT) intervention, and the RCT of Communicating Healthy Beginnings Advice by Telephone (CHAT) to Mothers with Infants to Prevent Childhood Obesity.

The intervention will be delivered for 12 months from 2 to 3 years. Starting from age 24 months when baseline measurements and randomisation are completed, three support sessions will be scheduled for 24-26, 28-30, and 32-34 months of the child’s age. The support sessions will include a telephone consultation with advice focussed on child feeding practices, physical activity and screen-time and developmental milestones. The advice from the consultation will be reinforced through SMS messages and a mail-out of written information.

A telephone protocol and manual will be developed to ensure consistency of intervention delivery based on our current trial. Telephone sessions will be delivered by a Child and Family Health Nurse trained in telephone support, health behaviour change strategies, and infant development. Based on our current trial experience, we anticipate that each telephone session will be ~20 minutes in duration. The nurse will employ a motivational interviewing approach and aim to set goals, build skills and knowledge, address barriers, and manage any anxiety or stress which may act as a barrier to health behaviour change. The nurse will make a written record of the session according to the telephone protocol. Adherence to the intervention will be assessed via review of telephone support written records. To assist, an intervention booklet will be developed according to the key messages that support the developmental milestones at each age and mailed to the participants one week prior to the telephone call.

Following each telephone session, we will then send two SMS messages per week for the next eight weeks (i.e., 16 SMS messages following each telephone call) to enhance and reinforce the support provided in the telephone session. Mothers will decide when (days of the week, times of day) they would like to receive the SMS. SMS wording will be tailored to: mother’s first name, child’s first name and age, and a partner’s name (or other nominated support person). Abbreviations will be kept to a minimum to align with mothers’ comprehension of SMS language. SMS will be generated and sent using a dedicated, secured web-based software program we used in the existing trial.
Intervention code [1] 312403 0
Intervention code [2] 312404 0
Comparator / control treatment
Mothers in the control group will receive usual care, which all mothers (including the intervention mothers) receive if needed from the government health service. This usual care is via early childhood health clinics operated by NSW Health, providing a free service for all new parents in NSW (while the child is aged 0-5 years). They are staffed by trained health professionals and registered nurses who specialise in child and family health. Mothers and parents can phone their local clinic to arrange an appointment. To maximise the control group retention rate, we will post home safety promotion materials and a newsletter on “Kids’ Safety” three times during the child's third year (age 2 - 3 years).
Control group

Primary outcome [1] 307411 0
Child's Body Mass Index
Timepoint [1] 307411 0
at child age 24 months and 36 months
Primary outcome [2] 307412 0
Child's Body Mass Index Z-score
Timepoint [2] 307412 0
at child age 24 months and 36 months
Secondary outcome [1] 351844 0
Child’s Fruit and Vegetable intake. Mothers will report their child’s eating habits using a validated short food frequency questionnaire (FFQ) specifically designed to assess children’s eating habits
Timepoint [1] 351844 0
at child age 24 months and 36 months
Secondary outcome [2] 351845 0
Child’s screen-based activities: mothers will report the total time their child spends doing screen-based activities per day in a usual week using a set of validated questions.
Timepoint [2] 351845 0
at child age 24 months and 36 months
Secondary outcome [3] 351846 0
Child’s outdoor play time: Mothers will report the total time their child spends doing outdoor play time as a proxy for active play time per day in a usual week using a set of validated questions.
Timepoint [3] 351846 0
at child age 24 months and 36 months
Secondary outcome [4] 351847 0
Mother’s nutrition (daily or weekly vegetable, fruit, soft drink, fast food consumption) self-reported by mother in study-specific survey, using questions sourced from the NSW Health Survey Program which we have used previously in HBT
Timepoint [4] 351847 0
at child age 24 months and 36 months
Secondary outcome [5] 351848 0
Mother’s physical activity assessed using questions sourced from the NSW Health Survey Program which we have used previously in HBT.
Timepoint [5] 351848 0
at child age 24 months and 36 months

Key inclusion criteria
The study participants from the existing CHAT 3-arm RCT will be invited to participate. These participants (pregnant women aged 16-50 years) were previously recruited from Sydney, South Eastern Sydney, South Western Sydney and Southern NSW Local Health Districts, and surrounding communities in NSW.
The children (both males and females) included in this study will be approximately 24 months of age at the time of recruitment.
Minimum age
22 Months
Maximum age
50 Years
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Mothers and their child will be excluded from the study if either have a severe medical condition based on advice given by doctors, or they have moved out of the study regions.

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Allocation is concealed with sealed opaque envelopes using block random number technique.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
After the baseline measurements, random allocation to either intervention or control group will be determined by a computer generated random number using random permuted blocks, stratified by the group allocation in the CHAT study. The use of stratified randomisation is to ensure that any carry-over effect of the previous intervention will be equally distributed between treatment groups in this study.

A research assistant who has no direct contact with participating women will be responsible for generating the random numbers and preparing the sealed opaque envelopes containing the group allocation.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
For the previous CHAT trial at 2 years, the sample size required was previously calculated in the published research protocol (1056 mothers: 352 in each of the 3 arms of the study). We recruited 1155 mothers into the trial (exceeding the required sample size by 100 mothers). It was estimated that a total sample size of 792 (264 per arm x 3) was needed at 2 years to have sufficient power to detect a difference in child BMI of 0.38kg/m2.

For this study we will need a total sample size of 506 (253 per arm x 2) by the end of the study (at child age 3 years). This would allow us to detect a difference of 0.40 kg/m2 in mean BMI (SD=1.60 based on HBT data), as significant at the 2-sided 5% significance level with 80% power. Allowing for a conservative 15% loss to follow-up between 2 and 3 years, we will need around 600 participants at 2 years of age.

In previous HBT follow up studies, re-consent rates were as high as 90 to 95%. In HBT, we recruited 667 participants, of whom 497 (75%) completed 2 years; 465 (94%) of these agreed to further follow-up, and 415 completed 3.5 years of follow-up, representing 62.2% of those initially recruited. If the same rates apply here, we would have 718 participants completing this study, allowing us to detect a difference of 0.335 kg/m2 in mean BMI.

Outcomes will be compared between the intervention group and the control group using intention-to-treat principles and CONSORT guidelines. For continuous variables, means will be compared using t-tests. For categorical variables, chi-squared tests will be used.

The primary analysis for this study will be adjusted for the stratification by the previous CHAT treatment group, as per CONSORT guidelines.

Secondary analyses will additionally adjust for exact age and will use multiple imputation to assess the effect of loss to follow-up.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment postcode(s) [1] 23966 0
2050 - Missenden Road
Recruitment postcode(s) [2] 23967 0
2170 - Liverpool
Recruitment postcode(s) [3] 23968 0
2194 - Campsie
Recruitment postcode(s) [4] 23969 0
2217 - Kogarah
Recruitment postcode(s) [5] 23970 0
2560 - Campbelltown
Recruitment postcode(s) [6] 23971 0
2031 - Randwick
Recruitment postcode(s) [7] 23972 0
2620 - Beard

Funding & Sponsors
Funding source category [1] 300659 0
Government body
Name [1] 300659 0
The NSW Ministry of Health Translational Research Grants Scheme
Address [1] 300659 0
73 Miller St North Sydney NSW 2060
Country [1] 300659 0
Primary sponsor type
A/Prof. Li Ming Wen
Health Promotion Unit, Sydney Local Health District
Level 9 North, King George V Building, Missenden Rd. Camperdown. NSW 2050
Secondary sponsor category [1] 300177 0
Name [1] 300177 0
Prof Chris Rissel
Address [1] 300177 0
Level 6, The Hub, D17 Charles Perkins Centre, The University of Sydney, Camperdown, NSW 2006.
Country [1] 300177 0

Ethics approval
Ethics application status
Submitted, not yet approved
Ethics committee name [1] 301444 0
SLHD Ethics Review Committee (RPAH Zone)
Ethics committee address [1] 301444 0
RPAH Research Ethics and Governance Office
Royal Prince Alfred Hospital
Missenden Road
Ethics committee country [1] 301444 0
Date submitted for ethics approval [1] 301444 0
Approval date [1] 301444 0
Ethics approval number [1] 301444 0

Brief summary
Childhood obesity is a serious public health challenge. About one in five Australian children aged 2 to 3 years is now either overweight or obese. Early intervention is important as excess weight and fast weight gain in early childhood are related to being overweight later in life with considerable impact upon health and health services.

Over the past 8 years we have developed, implemented and evaluated an early obesity intervention program funded by NHMRC. The project titled Healthy Beginnings Trial (HBT) was designed to improve infant feeding practices, eating habits, active play, and reduce TV viewing time to prevent childhood obesity in the first two years of life through staged home visiting. However, the high cost associated with home visits potentially limits population reach. To translate the successful evidence from the HBT into scaled-up practice applicable across the state with low-cost and broad-reach approaches, we commenced the CHAT study, to promote healthy infant feeding and active play using telephone support and Short Message Service (SMS).

Currently the CHAT trial is being conducted with 1155 mothers recruited from the third trimester of pregnancy, and their children are now approaching 24 months of age. The 24-month follow-up of the CHAT study will be an integral part of the recruitment process and baseline data collection for this new 2-arm RCT. By linking the two studies this study will add significant value to CHAT study by 1) examining the intervention effects at 2 years of age, and 2) conducting a new 2-arm RCT of an early obesity prevention program using a combined telephone support and SMS intervention for children aged 2-3 years. This study will address known gaps in universal obesity prevention strategies for children aged 0-2 years (CHAT study) and 2-3 years (this study) in the most efficient way possible. This unique opportunity of linking two studies will expedite project start up time and provide continuing support to the participants in the existing RCT.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 87022 0
A/Prof Li Ming Wen
Address 87022 0
Health Promotion Unit, Sydney Local Health District
Level 9 North, King George V Building, Missenden Rd.
Camperdown. NSW. 2050.
Country 87022 0
Phone 87022 0
+61 2 95159055
Fax 87022 0
+61 2 95159056
Email 87022 0
Contact person for public queries
Name 87023 0
A/Prof Li Ming Wen
Address 87023 0
Health Promotion Unit, Sydney Local Health District
Level 9 North, King George V Building, Missenden Rd.
Camperdown. NSW. 2050.
Country 87023 0
Phone 87023 0
+61 2 95159055
Fax 87023 0
+61 2 95159056
Email 87023 0
Contact person for scientific queries
Name 87024 0
A/Prof Li Ming Wen
Address 87024 0
Health Promotion Unit, Sydney Local Health District
Level 9 North, King George V Building, Missenden Rd.
Camperdown. NSW. 2050.
Country 87024 0
Phone 87024 0
+61 2 95159055
Fax 87024 0
+61 2 95159056
Email 87024 0

No data has been provided for results reporting
Summary results
Not applicable